When You See Six Magpies in Wales: Run, Forger, Run!

The submersion of Ker Ys

The Drowning of Ker Ys

Tasles of sunken cities are common in Celtic myth.

For example, there are:

Caer Ys of Breton myth,
Lyonesse, the English name given to the mythical lost coastal lands between Land’s End and Scilly of Cornish legend, known in Cornish as Lethowsow,
Cantref y Gwaelod (The Lowland Hundred), a drowned kingdom of Welsh legend in Cardigan Bay.
Maes Gwyddno (The Plain of Gwyddno) from a tale in the Black Book of Carmarthen, in which the land was flooded when a maiden whose job it was to keep watch over a well neglected her duties and the well overflowed.
Llys Helig (Helig’s Court) in Conway Bay. According to legend, the bells of the church can be heard from beneath the waves, and the palace can be seen at low tides.
Tír fo Thuinn (The Land under the Waves) is home to the Celtic sea god Manannán mac Lir (Son of the Sea).

Notice

At the request of the Consortium, certain geographical clues to the location of Llyn Ddu have been altered to prevent looters from discovering the site before it has been properly excavated. It is, of course, possible that the camouflage applied to this story will be insufficient, and that certain readers will be able to correctly guess the location of the site. If they do, they are kindly requested to keep that knowledge to themselves to help prevent this secret from becoming generally known and abused.